Generating Signals for WLAN 802.11ac Application Note Products: | R&S SMU200A | R&S SMATE200A | R&S SMBV100A | R&S SMJ100A | R&S SGS100A | R&S AMU200A | R&S AFQ100A | R&S AFQ100B | R&S ® WinIQSIM2 TM Rohde & Schwarz signal generators can generate standard-compliant WLAN IEEE 802.11ac signals up to 160 MHz bandwidth with excellent EVM performance. This application note demonstrates the generator test solutions and explains step-by- step how to configure a test signal. Several measurements are presented to illustrate EVM performance. Application Note C. Tröster 07.2012-1GP94_0E
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Generating Signals for WLAN 802.11ac Application Note
Products:
| R&SSMU200A
| R&SSMATE200A
| R&SSMBV100A
| R&SSMJ100A
| R&SSGS100A
| R&SAMU200A
| R&SAFQ100A
| R&SAFQ100B
| R&S®WinIQSIM2TM
Rohde & Schwarz signal generators can
generate standard-compliant WLAN IEEE
802.11ac signals up to 160 MHz bandwidth
with excellent EVM performance.
This application note demonstrates the
generator test solutions and explains step-by-
step how to configure a test signal. Several
measurements are presented to illustrate EVM
performance.
App
licat
ion
Not
e
C. T
röst
er
07.2
012-
1GP
94_0
E
Table of Contents
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 2
The elements of the transmission matrix (complex numbers w11, w12, …, w88) can be
used to configure the output signals (O1 to O8) by weighting the Tx signals
accordingly.
The output signals can be routed to a baseband output or saved to a file.
For example, the output signal O1 is routed to “Baseband A”. The following figure
illustrates this example.
Signal Configuration
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 19
baseband output
e.g. O1
RF A
RF B
RF up-
conversion
RF up-
conversion
File dump
Ma
pp
ing T
x a
nte
nna
s t
o
ou
tpu
t p
ath
s
For example, the output signal O2 is routed to “File”. The signal is saved to the hard
drive by entering a file path and name in the “File” column for O2.
The saved signal can be transferred to another instrument, e.g. with a USB stick, and
played back via the ARB generator of this instrument for MIMO testing.
4.2.5.1 Generating Tx Antenna Signals
By default, the diagonal elements of the transmission matrix (w11, w22, …, w88) are set
to 1, while all other matrix elements are set to 0.
Signal Configuration
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 20
In this case, the above formulas reduce to
O1 = Tx1
O2 = Tx2
O3 = Tx3
…
O8 = Tx8
One of these signals can be routed to the baseband output by selecting “Baseband A”
as output. After upconversion of the baseband signal, the selected Tx signal is present
at the RF output. For example, to generate the Tx1 signal, set O1 to “Baseband A”.
If a two-path signal generator, i.e. the SMATE, is used, one more signal can be routed
to the second baseband output by selecting “Baseband B” as output. After
upconversion of the baseband signal, the selected Tx signal is present at the second
RF output. For example, to generate the Tx2 signal in the second instrument path, set
O2 to “Baseband B”.
RF A
RF B
Tx 1
Tx 2
WLAN 11ac
DUT
The remaining Tx signals cannot be routed directly to a baseband output but can be
saved to a file by selecting “File” as output. The generated waveform files can then be
played back via the internal ARB generators of further instruments. For example, to
generate the Tx signals Tx3 to Tx8, e.g. six SMBVs 1 are needed. Each SMBV plays
back one of the generated waveform files and outputs the corresponding Tx signal at
the RF output.
4.2.5.2 Generating Rx Antenna Signals
In MIMO systems with transmit diversity or spatial multiplexing, multiple Tx signals are
transmitted. The receiver sees a superposition of these Tx signals. Such a composite
signal is termed Rx signal in this application note. The WLAN 11ac option makes it
possible to generate Rx signals as a weighted combination (amplitude and phase) of
up to eight Tx signals (in the following, only amplitude weighting is considered). Note
that this static weighting of Tx signals is not equivalent to a time-varying statistical
channel simulation. However, for many applications static weighting is already
sufficient for basic diversity and MIMO receiver testing. (For more demanding MIMO
tests with true channel simulation the realtime MIMO fading solution described in detail
in reference [2] is required.)
1 provided that the bandwidth of a Tx signal does not exceed 80 MHz. See section 3.1.
Signal Configuration
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 21
The Tx signals can be combined by setting the elements of the transmission matrix
(w11, w12, …, w88) to nonzero values. In the following example, four Tx antennas are
used.
If all matrix elements are set to 1 (no weighting), the above formulas give the following
output signals (O1 to O4):
O1 = Tx1 + Tx2 + Tx3 + Tx4 = Rx1
O2 = Tx1 + Tx2 + Tx3 + Tx4 = Rx2
O3 = Tx1 + Tx2 + Tx3 + Tx4 = Rx3
O4 = Tx1 + Tx2 + Tx3 + Tx4 = Rx4
In this case, the signals Rx1 to Rx4 are all equal. If all matrix elements are set to
values different than 1 (weighting), the above formulas give the following output signals
(O1 to O4):
Example:
O1 = Tx1 + 0.5Tx2 + Tx3 + 0.2Tx4 = Rx1
O2 = 0.8Tx1 + Tx2 + 0.2Tx3 + Tx4 = Rx2
O3 = 0.7Tx1 + 0.5Tx2 + 0.4Tx3 + Tx4 = Rx3
O4 = 0.2Tx1 + Tx2 + 0.8Tx3 + 0.6Tx4 = Rx4
In this case, the signals Rx1 to Rx4 differ. For example, signal Rx1 simulates the
situation where the antenna signals Tx1 and Tx3 reach the Rx antenna with full signal
strength while only 50 % of antenna signal Tx2 and 20 % of Tx4 are received.
One of the Rx signals can be routed to the baseband output by selecting “Baseband A”
as output. After upconversion of the baseband signal, the selected Rx signal is present
at the RF output. For example, to generate the Rx1 signal, set O1 to “Baseband A”.
If a two-path signal generator, i.e. the SMATE, is used, one more signal can be routed
to the second baseband output by selecting “Baseband B” as output. After
upconversion of the baseband signal, the selected Rx signal is present at the second
RF output. For example, to generate the Rx2 signal in the second instrument path, set
O2 to “Baseband B”.
Signal Configuration
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 22
f
f1 f2
Primary
segment
Seg.0
Secondary
segment
Seg.1
RF A
RF B
Rx 1
Rx 2
WLAN 11ac
DUT
The remaining Rx signals cannot be routed directly to a baseband output but can be
saved to a file by selecting “File” as output. The generated waveform files can then be
played back via the internal ARB generators of further instruments. For example, to
generate the Rx signals Rx3 and Rx4, e.g. two SMBVs 2 are needed. Each SMBV
plays back one of the generated waveform files and outputs the corresponding Rx
signal at the RF output.
Note that the required number of instruments (or more precisely, the number of
baseband generators/RF outputs) depends on the number of receive antennas at the
DUT that shall be tested simultaneously with different Rx signals. For example, if four
Tx antennas shall be simulated but only one Rx antenna at a time needs to be tested,
only one baseband/RF output, e.g. one SMBV 2, is needed. However, this sequential
testing of the Rx antennas is not real MIMO testing. To test four Rx antennas
simultaneously with different Rx signals, four basebands/RF outputs, e.g. four
SMBVs 2, are needed.
4.2.6 Special Case: Configuring an 80 MHz + 80 MHz Signal
For the 80 MHz + 80 MHz channel, there is an additional setting parameter in the
PPDU Configuration menu: Segment.
2 provided that the bandwidth of a Tx signal does not exceed 80 MHz. See section 3.1.
Signal Configuration
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 23
To generate the primary segment of the 80 MHz + 80 MHz signal, select “Seg.0”. To
generate the secondary segment, select “Seg.1”. Selecting “Both” is only possible if the
transmission bandwidth is set to 160 MHz in the main menu. The two segments are
generated contiguously in this case.
4.2.6.1 Generating an 80 MHz + 80 MHz Signal with the AFQ
Contiguous
To generate the two 80 MHz segments contiguously, set the “Segment” parameter to
“Both”.
Noncontiguous
To generate the two 80 MHz segments noncontiguously, perform the following steps in
WinIQSIM2:
1 Generate the primary segment and the save signal as a waveform file
2 Generate the secondary segment and the save signal as a waveform file
3 Combine both waveforms using the ARB multi carrier function
Step 1: Set the “Segment” parameter to “Seg.0” and configure the signal as desired.
Click the “Generate Waveform File” button 3 in the main menu to save the signal (e.g.
as “primary_seg.wv”).
Step 2: Return to the PPDU Configuration menu and set the “Segment” parameter to
“Seg.1”. Again, click the “Generate Waveform File” button in the main menu to save
the signal (e.g. as “secondary_seg.wv”).
Step 3: Open the ARB Multi Carrier menu and set the number of carriers to “2”. Enter
the desired carrier spacing, e.g. 400 MHz. Click the “Carrier Table” button.
In the carrier table, set the “State” to “On” for both carriers. For carrier 0, select the
primary segment waveform as “File”. For carrier 1, select the secondary segment
waveform as “File”.
3 This button saves the baseband output signal that is routed to “Baseband A” in the “TX Antenna Setup”
menu.
Signal Configuration
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 24
3x WLAN 11n WLAN 11a WLAN 11ac
SIM2/Waveforms/primary_seg
2/Waveforms/secondary_seg
In the main menu, set the “State” to “On” and transfer the multi carrier signal (i.e. the
80 MHz + 80 MHz signal) to the AFQ B for playback.
Note that the AFQ A is not suitable for noncontiguous 80 MHz + 80 MHz signal generation. For the AFQ B, the maximum (meaningful) carrier spacing of the two segments is 400 MHz.
4.3 Configuring WLAN Multistandard Signals
WLAN 11ac devices must be able to communicate with earlier generation devices operating in the 5 GHz band using the predecessor standards, WLAN 11a and 11n. For cross-standard testing, the user can define realistic multistandard signals via the Frame Blocks Configuration menu. Open this menu by clicking the “Frame Block Configuration…” button in the main menu. Use the “Append” button to add new frame blocks (i.e. new lines) to the list and create a sequence of frame blocks in this way. Each frame block can be configured individually. For example, the number of frames within this block can be set. Also the PPDU settings are configured individually for each block. To generate WLAN 11n and 11ac frames, choose “Mixed Mode” as “Physical Mode” and define the high throughput (HT) or VHT channel to use. To generate WLAN 11a frames, choose “Legacy” as “Physical Mode” and define the channel to use. As shown in the above figure, switching between different WLAN signals is easy to do, making multistandard testing straightforward.
Verification Measurements
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 25
5 Verification Measurements Rohde & Schwarz signal and spectrum analyzers can analyze WLAN 11ac transmitter
signals in two different ways:
Analysis using the R&S®FSx-K96 general purpose OFDM analysis software.
This method is described in the application note “Measurement of WLAN
802.11 ac signals” (1EF82).
Analysis using the on-instrument WLAN application R&S®FSx-K91ac. This
method is recommended for analysis and used in this application note to
perform measurements.
The verification measurements presented in this application note were performed using
an FSW with an analysis bandwidth of 160 MHz in the following setup:
I Q
RF
10 MHz reference
10 MHz
reference
5.1 EVM Measurement
To obtain optimal EVM results, the following settings should be made:
Generator:
The “Time Domain Windowing Active” parameter in the PPDU Configuration
menu is disabled by default. Leave this parameter disabled.
When using an AFQ setup, optimize the EVM as described in section 6.1.
Analyzer:
Set the “Channel Estimate” parameter to “Payload” in the Tracking/Channel
Estimation menu. (All EVM measurements presented in this application note
are performed with payload-based channel estimation.)
Adjust the RF attenuation.
Optimize the reference level such that the R&S®FSx is about to show the IF
overload warning.
Verification Measurements
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 26
For example, an AFQ with an SGS as upconverter is used to generate a 160 MHz
signal. The setup is optimized as described in section 6.1. The RF level of the SGS is
set to 0.0 dBm. On the FSW, the RF attenuation is set to 10 dB. The reference level is
adjusted to 10 dBm. (At 9 dBm the FSW shows the “IF OVLD” warning.) The following
result is obtained:
The measured EVM is –47.3 dB (0.43 %) for a 160 MHz signal with 256 QAM
modulation.
5.2 Channel Power Measurement
When performing a channel power measurement of a WLAN Tx signal, one needs to
take into account that there are signal gaps between the WLAN frames if the “Idle
Time” parameter is set to nonzero values in the Frame Blocks Configuration menu.
The measured average RF power will thus be lower than the RF level set at the
generator, as the latter relates only to the “frame active” part of the signal. To obtain a
correct channel power measurement, the following settings should be made:
Generator:
When using an AFQ setup, do not forget to adjust the “Crest factor” parameter
in the upconverter for correct leveling as described in section 3.2.3.
When using a combiner in the setup, consider the specified insertion loss.
Analyzer:
Use a gated trigger to measure the signal only during bursts. Use “IF Power”
as trigger source and adjust the trigger level. Set the gate length such that only
the burst is captured and not the gap.
Verification Measurements
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 27
For example, an AFQ with an SGS is used as upconverter to generate an 80 MHz
signal. The RF level of the SGS is set to 0.0 dBm. The following result is obtained.
The measured channel power is –1.0 dBm. The result matches (apart from cable loss)
the RF level set at the SGS.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 28
6 Optimizing Signal Quality for AFQ Setups If the WLAN 11ac signal is generated with an AFQ and an upconverter, the signal
quality is very good but the external cabling is a potential source of impairment. The
cabling can lead to I/Q imbalances and consequently to image OFDM carriers in the
RF signal. These overlay and thus impair the actual OFDM carriers, resulting in a
suboptimal EVM. Therefore, due to the external cabling, the signal quality of an AFQ
setup may not be as good as it could be. Even if achieving better signal quality for
testing is not relevant to your application, we nevertheless want to explain in this
section how to configure the AFQ setup to attain optimal performance. For the
optimization, it does not matter which Rohde & Schwarz signal generator is used for
upconversion (although the best results are achieved with the SGS).
As an example, the AFQ-SGS setup is used for the measurements presented in this
section. They were performed using an FSW with an analysis bandwidth of 160 MHz.
I Q
RF
10 MHz reference
10 MHz
reference
6.1 Optimizing EVM Performance
6.1.1 Optimization Tool
A software tool that can be used to optimize the EVM result for AFQ setups is available
free of charge. The software can be downloaded from the Rohde & Schwarz website:
Products Signal Generators Baseband AFQ Downloads Software
R&S SMx RF and BB Correction Toolkit
As mentioned above, the external cabling can lead to image OFDM carriers that impair
the signal and degrade EVM performance. The provided software automatically
configures the equalizer of the AFQ to compensate the image carriers. The necessary
measurement is performed with the connected upconverter (e.g. SGS) and a spectrum
analyzer.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 29
I Q
RF
10 MHz
reference
10 MHz
reference
AFQ
SGS
FSW
Remote
control
R&S SMx RF and
BB Correction
Toolkit
Open the software and select “AFQ Calibration” under the “Configuration” tab. Select
the 10 MHz reference source.
Next, configure the three instruments of the setup: AFQ, SGS (or SMx) and R&S®FSx.
Select the instrument and click the “Configure..” button.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 30
Select the remote interface, e.g. “TCPIP/VISA”. Connect the instrument via LAN to the
control PC and enter the IP address of the instrument. Use the “Test Connection”
button to quickly test the remote connection.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 31
Under the “Configuration” tab in the main menu, press the “Init >>” button. If the
software reports “Initializing instruments ok.”, switch to the “AFQ Calibration” tab.
Select the RF frequency and RF level to be used for calibration and later for testing.
Select the single-ended baseband output level of the AFQ. Use the following values:
AFQ A: 500 mV
AFQ B: 500 mV with “Enable Bias” checkbox enabled (recommended)
AFQ B: 350 mV with “Enable Bias” checkbox disabled
If the bias amplifier of the AFQ B is not enabled, the EVM result is slightly better than
with amplification, since every amplifier introduces a certain degree of distortion.
However, the output level of the AFQ B is then limited to 700 mV (balanced output),
and consequently the RF level at the SGS is no longer correct (see section 3.2.3 for
background). The actual RF level is 3.1 dB lower than the set/displayed level on the
SGS (or SMx).
Start the calibration by pressing the “Output Resp. and Imb.” button. While the
calibration is running, the following window is displayed:
If the software reports “Correction ok.”, the calibration is completed and the following
result summary is displayed:
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 32
On the AFQ, click the “Local“ icon in the toolbar to switch from remote to local
operation. The AFQ block diagram looks like this:
Note that the software configures both equalizers of the AFQ: “Modulator” and “I/Q”.
The equalizer “Modulator” is used to compensate the RF
frequency response of the upconverter (e.g. SGS).
The equalizer “I/Q” is used to compensate I/Q imbalances and
thus the image carriers.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 33
When operating the AFQ B with 350 mV and inactive bias amplifier, the following error
message may appear on the AFQ B:
There are two ways to remove this error:
Click the “config” button in the “Equalizer” block and select “Modulator”. Set the
“State” to “Off”. This disables the RF frequency response correction which is
not necessarily needed, because the DUT (like the FSW) can equalize the
frequency response of the received signal through channel estimation.
Alternatively, leave the RF frequency response correction enabled. Slightly
reduce the baseband output level of the AFQ (amplitude setting) until the error
message vanishes. Be aware that the actual RF level differs from the
set/displayed level on the SGS (or SMx) by slightly more than 3.1 dB in this
case.
Click the “config” button in the “Equalizer” block and select “I/Q”. The “State” must be
“On”, i.e. the baseband I/Q correction must be enabled. The “BBCalibI” and
“BBCalibQ” files are generated and loaded automatically by the software tool.
The last step is to load the wanted WLAN waveform and activate the ARB.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 34
Compared with the RF frequency response correction (which can be disabled), the
baseband I/Q correction is more robust against RF frequency and level changes on the
SGS (or SMx). However, for optimal performance the calibration should be repeated if
the RF frequency and level changes
the AFQ baseband output level changes
If the setup changes, e.g. if the cables are exchanged or swapped, the calibration must
be repeated.
Refer also to the software manuals that come with the installation of the software.
The following screenshots show the EVM measured before and after the calibration.
The measured EVM for a 160 MHz signal with 256 QAM modulation is –44 dB before
and –47 dB after the calibration.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 35
6.1.2 Manual EVM Optimization
To optimize the EVM, it is strongly recommended to use the software tool, since the
equalizer of the AFQ compensates I/Q imbalances frequency-selectively. However, the
EVM can also be optimized manually, e.g. in case there is no R&S®FSx available.
Slightly unequal electrical cable lengths introduce a delay between the I and Q signals.
This delay leads to image OFDM carriers and is the biggest contribution to a degraded
EVM.
The delay can be compensated by adjusting the I and Q path delay of the Δt / Δf
settings on the AFQ.
In addition, the I and Q signals may have small amplitude imbalances. They can be
compensated by adjusting the I and Q gain of the I/Q impairments settings on the AFQ.
The following screenshots show the EVM measured before and after adjusting the I
and Q path delay such that the initial delay between the I and Q signals is cancelled.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 36
The measured EVM for an 80 MHz signal with 256 QAM modulation is –45 dB before
and –47 dB after the adjustment.
Note that this manual optimization method does not use the equalizer of the AFQ and
is thus not frequency-selective.
6.2 Minimizing Carrier Leakage
6.2.1 Optimization Tool
The software tool described in section 6.1.1 also minimizes the carrier leakage
automatically during the calibration.
Optimizing Signal Quality for AFQ Setups
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 37
6.2.2 Manual Carrier Leakage Optimization
The following figure shows the spectrum of a WLAN 11ac signal. The sweep time
setting on the analyzer was chosen such that the spectrum reveals the carrier leakage
in the RF signal.
The carrier leakage is caused by a DC component in the I/Q signal. It can be
suppressed by adjusting the I and Q offset of the I/Q impairments settings in the
upconverter.
The following figure shows the spectrum after adjusting the I and Q offset such that the
center carrier is optimally suppressed.
Note that the carrier leakage has no effect on the measured EVM of the WLAN 11ac
signal (since there is no OFDM carrier at the carrier frequency).
PER Testing
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 38
RF test signal
WLAN 11ac
DUT
Control SWPER calculation
7 PER Testing The Rohde & Schwarz WLAN 11ac test solution supports packet error rate (PER)
testing via the nonsignaling mode. It is possible to generate standard-compliant test
signals including MAC header.
To configure the MAC header, click the “Configure MAC Header and FCS…” button in
the PPDU Configuration menu.
Activate the MAC Header and the frame check sequence (FCS) and optionally enable
the sequence control field.
To perform nonsignaling PER measurements, the MAC header settings do not need to
be configured but can be left at their default values. This generally works fine. The
user’s equipment4 analyzes the transmitted FCS to evaluate if packets sent from the
generator to the DUT were received error-free. All erroneous packets are counted and
a PER (ratio between erroneous packets and total number of packets) is calculated.
The user’s equipment can further determine missing or retransmitted frames by
evaluating the sequence control field.
4 The control and evaluation software is generally provided by the WLAN device manufacturer.
PER Testing
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 39
For PER measurements, e.g. 1000 frames are generated and evaluated. Set the
desired number of frames in the Frame Blocks Configuration menu.
On the instrument, use the “Single” trigger mode to output the 1000 frames exactly
once. The Trigger menu can be opened by clicking the “Trigger/Marker…” button in the
main menu of the WLAN option or the ARB.
MIMO Testing
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 40
8 MIMO Testing
Test signals
Standard-compliant signals for testing MIMO devices can be easily generated. Up to
eight Tx antenna signals can be created. It is even possible to generate different Rx
antenna signals. See section 4.2.5 for details.
Realtime fading
Fading can be applied to the test signals by using the SMU and AMU signals
generators. These instruments support realtime fading for true channel simulation. See
reference [2] for details.
Synchronizing multiple instruments
Multiple SMBVs can be synchronized with ultrahigh precision using the master-slave
mode of the instrument. See reference [4] for details.
Multiple AFQs can be synchronized with ultrahigh precision using the master-slave
mode of the instrument. The master AFQ must be triggered externally. See reference
[5] for details.
The two internal baseband generators in a single SMU/SMATE/AMU can be
synchronized with very high precision by using the first baseband generator to trigger
the second one. See section 3.2.2 for details.
Multiple SMUs/SMATEs/SMJs/AMUs can be synchronized with very high precision by
triggering all internal baseband generators with a common external trigger signal. See
reference [2] for details.
Abbreviations
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 41
9 Abbreviations ARB Arbitrary waveform generator
BCC Binary convolution coding
CSD Cyclic shift delay
DUT Device under test
EVM Error vector magnitude
I/Q In-phase/quadrature
IDFT Inverse discrete Fourier transformation
LDPC Low density parity check
MAC Media access control
MIMO Multiple input multiple output
MCS Modulation and coding scheme
OFDM Orthogonal frequency-division multiplexing
PER Packet error rate
PLCP Physical layer convergence protocol
PPDU PLCP protocol data unit
RF Radio frequency
RMS Root mean square
Rx Receive
STBC Space time block coding
SW Software
Tx Transmit
VHT Very high throughput
WLAN Wireless local area network
10 References [1] Rohde & Schwarz Application Note, “Connectivity of Rohde & Schwarz Signal
Generators” (1GP72)
[2] Rohde & Schwarz Application Note, “Guidelines for MIMO Test Setups – Part
2” (1GP51)
[3] Rohde & Schwarz White Paper, “802.11ac Technology Introduction” (1MA192)
1GP94_0E Rohde & Schwarz Generating Signals for WLAN 802.11ac 42
11 Ordering Information Please visit the Rohde & Schwarz product websites at www.rohde-schwarz.com for comprehensive ordering information on the following Rohde & Schwarz signal generators:
R&S®SMU200A vector signal generator
R&S®SMATE200A vector signal generator
R&S®SMBV100A vector signal generator
R&S®SMJ100A vector signal generator
R&S®AMU200A baseband signal generator and fading simulator
R&S®AFQ100A I/Q modulation generator
R&S®AFQ100B UWB Signal and I/Q modulation generator